Paver Sand Calculator
Installing patio pavers or a flagstone walk? Calculate how much bedding sand (the 1" leveling layer below the pavers) and polymeric joint sand (to fill the cracks between them) your area needs.
Results
Two completely different types of sand
When laying standard patio pavers, flagstones, or interlocking brick systems, you will need two entirely distinct categories of sand. Confusing the two or attempting to substitute one for the other is a common DIY mistake that leads to structural failures.
A professional paver project uses:
- Bedding Sand (Leveling Sand): This is a coarse, sharp, angular sand (typically meeting ASTM C33 standards). It does not pack together into a solid chunk; instead, the sharp grains interlock and cushion the individual pavers, keeping them perfectly flat and level.
- Polymeric Joint Sand: This is a very fine sand infused with dry polymer binders. After laying the pavers, you sweep this fine sand into the cracks, mist it with water, and the polymers activate, drying into a rubbery, water-resistant joint that prevents weed growth, deters ants, and stops erosion.
The bedding sand formula
Bedding sand is traditionally laid exactly 1 inch thick over a highly compacted gravel base. Laying sand thicker than 1 inch will actually cause pavers to sag or shift underfoot, as the uncompacted sand layer shifts over time.
To calculate the bags of bedding sand needed:
cubic feet = area in sq ft × (depth in inches ÷ 12), and then bags (50 lb) = (cubic feet × 100 lbs/cu ft × waste factor) ÷ 50.
| Patio Size | Area | Cubic Yards | 50 lb Bags of Sand |
|---|---|---|---|
| 10 × 10 ft patio | 100 sq ft | 0.34 cu yd | 19 bags |
| 15 × 15 ft patio | 225 sq ft | 0.76 cu yd | 42 bags |
| 20 × 20 ft patio | 400 sq ft | 1.36 cu yd | 74 bags |
Polymeric sand coverage estimates
Polymeric sand is expensive (usually $30 to $60 per 50 lb bag) and is packed with dry polymers, so getting the quantity correct matters for your budget. Coverage depends entirely on the size of the gaps between the paving units:
| Joint Style | Gap Width | Estimated Coverage per Bag | Typical Paver Types |
|---|---|---|---|
| Narrow Joints | 1/16" to 1/8" | 75 to 90 sq ft | Interlocking concrete pavers, brick pavers |
| Wide Joints | 1/4" to 1/2" | 35 to 50 sq ft | Natural slate flagstones, cobblestone, fieldstone |
Frequently asked questions
Can I use play sand under pavers?
No. Play sand consists of rounded grains that slide past each other under weight, causing pavers to sink and shift. Use sharp, angular bedding sand (concrete sand / ASTM C33) to ensure interlocking stability.
What is the correct depth of bedding sand?
Always lay bedding sand exactly 1 inch thick. Laying it deeper than 1 inch makes the base spongy and leads to settling and uneven pavers.
How long does polymeric sand take to cure?
Standard polymeric sand takes 24 to 48 hours of warm, dry weather to cure completely. Do not walk or drive on the pavers, and protect them from heavy rainfall, until the curing process is complete.
Can you put polymeric sand on wet pavers?
No. Pavers must be completely dry before sweeping polymeric sand. Any moisture on the surface will activate the binders instantly, gluing sand to the face of the pavers and causing permanent staining.